| Agricultural sciences |
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| Effects of four arbuscular mycorrhizal fungi on tolerance of Vaccinium corymbosum to drought stress |
| XU Qinglong, LIU Xiaomin, XU Xiaobing, LI Qingqing, ZHANG Hong, XIAO Jiaxin* |
| (Key Laboratory for the Conservation and Utilization of Important Biological Resources in Anhui Province, College of Life Sciences, Anhui Normal University, Wuhu 241000, Anhui, China) |
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Abstract
Blueberry (Vaccinium spp.) is well known for its rich anthocyanins and other bioactive compounds, which helps preventing from cardiovascular disease and other chronic illnesses. Over the past decades, blueberry has been cultured in many areas of China, thus became the fastestgrowing species in fruit production, potentially making China one of the largest blueberryproducing countries in the world. However, blueberry growth and production were severely affected by drought events in areas of Yangtze River. Vaccinium plants preferred acidic soils and spontaneously formed mutualistic symbiotic associations mainly with soil fungi of the phylum Ascomycota, called ‘ericoid mycorrhizae’. However, some reports have indicated that the absence of ericoid mycorrhizal fungi inoculum may allow Vaccinium plants to associate with arbuscular mycorrhizal (AM) fungi, and AM fungi inoculation significantly enhanced growth of Vaccinium plants. Southern highbush blueberry (Vaccinium corymbosum) has short or even rare root hairs in field systems, and depends on fungi for optimal growth. Meanwhile, few reports were about the effects of AM fungi on osmotic adjustment and reactive oxygen metabolism of southern highbush blueberry.
The purpose of this study is to evaluate the effects of Glomus mosseae, G. versiforme, G. intraradices and G. etunicatum on the southern highbush blueberry seedlings under drought stress conditions, and antioxidant and osmotic adjustment matters, mineral nutrition in blueberry plants and enzymatic activities in rhizosphere soil were investigated.
Two soil water regimes (wellwatered ［WW］ and drought stress ［DS］) and five AM fungi inoculations (four Glomus and non-AM fungi inoculation ［CK］) were arranged in a complete randomized block design. Each treatment (one plant per pot) was performed in three replicates. Water treatments began after 134 days (July 31, 2014) adaption of greenhouse conditions, and WW pots were maintained, but DS pots were cut off for 20 days of water supply and resumed on August 20. Meanwhile, the leaves of blueberry cultivar Misty plants were collected for determination of physiological index on 13 d drought, 20 d drought and 2 d rewatering, respectively.
The results showed that the leaf relative water content (RWC) and chlorophyll contents decreased in DS treatments, while the soluble sugar content, superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents increased, but had no significant effects on mycorrhizal colonization. Under the DS conditions, leaf RWC, chlorophyll, soluble sugar contents and SOD activity were significantly higher in AM fungiinoculated plants, especially in G. mosseaeinoculated plants than in non-AM fungi inoculated plants, while the leaf MDA content was lower. In addition, AM fungi, especially G. mosseae, increased phosphorus (P) and potassium (K) contents in the leaves, stems and roots, as well as acid phosphatase (ACP), catalase (CAT) and urease activities in rhizosphere soil of blueberry plants, in comparison with the nonAM fungiinoculated treatment (CK).
These results indicate that the drought tolerance of blueberry cultivar Misty is enhanced with AM fungi inoculation through increase of antioxidant enzyme and osmotic adjustment, and the soil environment is improved, accompanied by P and K uptake increases by plants. In addition, G. mosseae is the most beneficial Glomus among the four AM fungi to improve the resistance of blueberry cultivar Misty plants against DS.
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Published: 20 July 2016
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4种丛枝菌根真菌对南高丛蓝莓抗旱性的影响
采用盆栽试验研究摩西球囊霉（Glomus mosseae)、地表球囊霉（G. versiforme）、根内球囊霉（G. intraradices）和幼套球囊霉（G. etunicatum）4种丛枝菌根（arbuscular mycorrhizal，AM）真菌接种南高丛蓝莓（Vaccinium corymbosum）品种薄雾对干旱胁迫的生理生化反应。结果表明：干旱胁迫降低了叶片相对含水量与叶绿素含量，增加了可溶性糖含量、超氧化物歧化酶（superoxide dismutase，SOD）活性与丙二醛（malondialdehyde，MDA）含量，但对菌根侵染率的影响较小；在干旱胁迫下，4种AM真菌尤其是摩西球囊霉接种株相对含水量、叶绿素和可溶性糖含量、叶片SOD活性均显著高于未接种株，而接种株叶片MDA含量相对低于未接种株；另外，AM真菌接种处理能够提高蓝莓植株根、茎、叶的磷和钾含量以及根围土壤酸性磷酸酶、脲酶和过氧化氢酶活性，尤以摩西球囊霉处理最为明显。总之，4种AM真菌接种处理提高了蓝莓品种薄雾植株的抗旱性，以摩西球囊霉的效果最好。
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